Device and method for cutting semiconductor-crystal bars

Abstract

A plurality of wires are stretched in parallel through wire supplying-winding apparatuses and wire-tension adjusting apparatuses. A semiconductor-crystal bar is affixed on an ascent/descent table via a feeding table. The ascent/descent table is capable of being driven to ascend or descend by the ascent/descent apparatus. The wires and the semiconductor-crystal bar are dipped into a high-insulation oil, and discharging is created therebetween to perform cutting. If the resistance of the semiconductor-crystal bar exceeds 1 Ω·cm, used inert gas is filled into a space within the interior space of an airtight vessel. Then, the high-insulation oil is heated by heaters and is kept at a temperature higher than 150° C. to reduce the resistance of the semiconductor-crystal bar. Therefore, cutting is easily performed. The used inert gas can prevent fire from occurring due to the flaming of the high-insulation oil.

What is claimed is: 
     
       1. A device for cutting a semiconductor-crystal bar comprising: a plurality of wires stretched in parallel;   means for shifting said wires constantly in an axial direction of said wires;   means for supplying electric current to said wires;   means for heating a high-insulation oil into which said wires and the semiconductor-crystal bar to be cut are dipped;   means for holding the semiconductor-crystal bar and shifting the semiconductor-crystal bar relative to said wires in the vertical and the horizontal directions;   an airtight vessel for accommodating said shifting means, supplying means, heating means and holding means therein;   means for supplying and expelling inert gas that is filled into a space within said airtight vessel and above the high-insulation oil; and   means for supplying and expelling the high-insulation oil.   
     
     
       2. A method for cutting a semiconductor-crystal bar comprising the steps of: providing a plurality of stretched cutting wires for cutting the semiconductor-crystal bar;   supplying electric current to the stretched wires; and   cutting the semiconductor-crystal bar through electric discharging rendered by the electric current.   
     
     
       3. The method for cutting a semiconductor-crystal bar as claimed in claim 1, wherein said cutting operation is performed after heating the semiconductor-crystal bar to a temperature higher than room temperature. 
     
     
       4. The method for cutting a semiconductor-crystal bar as claimed in claim 3, wherein when the resistance of the semiconductor-crystal bar exceeds 1 Ω·cm, the semiconductor-crystal bar is heated. 
     
     
       5. The method for cutting a semiconductor-crystal bar as claimed in claim 2, wherein cutting is performed in an inert gas atmosphere. 
     
     
       6. The method for cutting a semiconductor-crystal bar as claimed in claim 2, wherein said method further comprises the steps of: providing an airtight vessel;   filling a portion of the airtight vessel with a high insulation oil;   filling inert gas into a space within the airtight vessel and above the high-insulation oil stored therein, and creating electric discharging between the semiconductor-crystal bar and the wires while at least part of the wires and the semiconductor-crystal bar are dipped into the high-insulation oil, wherein said cutting operation is performed after the process of heating and keeping the high-insulation oil at a temperature higher than 150° C. to reduce the resistance of the semiconductor-crystal bar.   
     
     
       7. A device for cutting a semiconductor-crystal bar comprising: a plurality of wires stretched in parallel;   a winding apparatus for shifting said wires in an axial direction of said wires;   an electrode for supplying electric current to said wires;   a heater for heating a high-insulation oil into which said wires and the semiconductor-crystal bar to be cut are dipped;   a table support for supporting the semiconductor-crystal bar;   an airtight vessel for accommodating said winding apparatus, electrode, heater and table support therein;   a first gas conduit for supplying an inert gas into a space within said airtight vessel above the high-insulation oil;   a second gas conduit for expelling the inert gas from said airtight vessel;   a first oil conduit for supplying the high-insulation oil to the airtight vessel; and   a second oil conduit for expelling the high-insulation oil from the airtight vessel.